Unit 2 Ecosystem.pdf

Environmental Studies: Ecosystem  Introduction The term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley. Ecosystem: A self-regulating group of biotic communities of species interacting with one another and with th...

Environmental Studies: Ecosystem  Introduction The term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley. Ecosystem: A self-regulating group of biotic communities of species interacting with one another and with their non-living environment exchanging energy and matter The term oekologie (ecology)was coined by the German biologist Ernst Haeckel in the year 1866. Greek word “Oikos” meaning “home” and “logos” meaning “study” Ecology: The study of organisms in their natural habitat interacting with their surroundings This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination quesions will be in depth and can be solved by following text book only. Classification of Ecosystems Natural Ecosystems Terrestrial Ecosystems Man-made Ecosystems (aquaria, garden, dams & cropland of Forest maize, wheat, rice). Ecosystems Grass land Aquatic Ecosystems Ecosystems Desert Ecosystems Fresh water Ecosystems Standing water Running water Marine Ecosystems (lentic) Ecosystems (lotic) Ecosystems Natural Ecosystems Man-made Ecosystems  Natural Vs Artificial Ecosystems Natural Ecosystem Artificial Ecosystem (i) Plants of one species are often (i) Plants of the different species grow scattered. in close proximity. (ii) Natural ecosystems usually have (ii) Artificial ecosystems usually contain alternate sources of food available if less food choices. one fails. (iii) Natural ecosystem is developed (iii) Artificial ecosystem is created and under natural conditions. manipulated by human activities. (iv) In a natural ecosystem the inorganic (iv) In artificial ecosystems, the nutrients are returned to the soil from inorganic nutrients do not return to which they were taken. the soil but are carried away at some other places. (v) Natural ecosystems have no distinct (v) Artificial ecosystems have distinct boundaries. boundaries. Structure of Ecosystem  Biotic Components of Ecosystems Producers (or autotrophs) Green plants and some bacteria which manufacture their own food. Consumers (or heterotrophs) Animals which obtain their food from producers Primary consumers = herbivores Secondary consumers = carnivores Tertiary consumers = top carnivorous Decomposers Bacteria and fungi that decompose dead organic matter and convert it into simpler parts This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Abiotic Components of an Ecosystem Physical Factors Rainfall Humidity Temperature Nature of soil Water currents Sunlight Chemical Factors Percentage of Water and air in soil Salinity of Water Oxygen dissolved in water Nutrients present in soil Limiting Factors Food, water, shelter and space are limiting factors for the growth of population of human and animals.  Functions of an Ecosystem  Food chain and food web ( food chain is a series of organisms that eat one another so that energy and nutrients flow from one to the next. Many food chains interacts to form food web)  Energy flow (The energy flow takes place via the food chain and food web)  Ecological pyramids (An ecological pyramid is a graphical representation designed to show the biomass or bio productivity at each trophic level in a given ecosystem)  Limiting Factors Factors which restrict the further growth of population – Availability of food – Water – Shelter – Space This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth  Functional unit Food chain (sequence of eating and being eaten), food web, trophic structure Energy flow Cycling of nutrients  Food Chain The transfer of food energy from the source (plants) through a series of organisms by repeated eating and being eaten up is referred to as food chain. Types: Grazing food chain-a common chain starting with plant or plant product Detritus food chain-chain derived by the organic wastes and dead matter from grazing food chains Trophic Level  Food web The interlocking pattern formed by several food chains that are linked together is called a food web.  Energy Flow in Ecosystems First Law of Thermodynamics energy can neither be created nor destroyed but only is transformed from one form to another. Second Law of Thermodynamics-The second law of thermodynamics states that no energy transformations are 100% efficient. 10 Percent Rule of Energy As a rule of thumb, 90 percent of the energy involved is degraded at each tropic transfer and only 10 percent of the energy is conserved in the organism's tissue.  Biogeochemical cycles Types: Gaseous Cycle: Nitrogen, Oxygen, Carbon Sedimentary Cycle: Phosphorus, Sulphur  Nutrient cycles Nitrogen  Nutrient cycles Carbon  Nutrient cycles Phosphorus  Ecological Pyramid The graphical representations of different tropic levels in an ecosystem where producers occupy the base and the top consumer occupy the apex of the pyramid, is known as ecological pyramid. They are used to illustrate the feeding relationships between organisms. Types of Ecological Pyramids Pyramid of number = no of individual at each tropic level is considered Pyramid of biomass = biomass at each tropic level is considered Pyramid of energy = energy at each tropic level is considered  Pyramid of Number Pyramid of number is used to show the number of individuals in each tropic level. It is upright in case of grassland and pond ecosystems. Pyramid of Number Pyramid of Biomass tertiary consumers 75 g/m2 Pyramid of biomass records the total dry organic matter of organisms at each trophic level in a secondary 150g/m2 given area of an ecosystem. consumers The pyramid of biomass is used to show the total biomass of individuals primary at each trophic level. consumers 675g/m2 It is better than the pyramid of number for showing the relationships between organisms. producers 2000g/m2 24 Pyramid of Biomass Pyramid of energy Pyramid of energy is used to show the amount of energy transferred between tropic levels. It provides the best representation of the overall nature of an ecosystem. The pyramid of energy flow is always upright because there is always loss of energy while moving from lower tropic level to higher tropic level. Therefore, the energy reaching the next tropic level is always less compared to that in the previous tropic level.  Ecological Succession Ecological succession is the slow process by which ecosystems change and develop over time. It is therefore a series of predictable temporary communities or stages leading up to a climax community. Each stage/temporary community is called a successional stage. Each step prepares the land for the next successional stage. All habitats are in the state of constant ecological succession. Ecological Succession is an orderly sequence of different communities over a period of time. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only. 27 This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only. 28  The Climax Community A climax community is a mature, stable community that is the final stage of ecological succession. In an ecosystem with a climax community, the conditions continue to be suitable for all the members of the community. Any particular region has its own set of climax species, which are the plants that are best adapted for the area and will persist after succession has finished, until another disturbance clears the area. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only. 29 These are Climax Communities 30 30 Types of ecological succession Primary Succession Secondary Succession : 31 Primary succession is the process by which an area first changes from bare rock into a functioning ecosystem. 32  Secondary Succession SECONDARY SUCCESSION begins in habitats where communities were entirely or partially destroyed by some kind of damaging event. When an existing community has been cleared by a disturbance such as a fire, tornado, etc...and the soil remains intact, the area begins to return to its natural community. Because these habitats previously supported life, secondary succession, unlike primary succession, begins on substrates that already bear soil. In addition, the soil contains a native seed bank. Since the soil is already in place, secondary succession can take place five to ten times faster than primary succession. 33 Secondary succession is the process by which an ecosystem that has been destroyed gradually returns to its previous state. 34 The Circle of Life in Secondary Succession 35  Process / Stages of Ecological Succession Nudation- Succession begins with the development of a bare site, called Nudation (disturbance). Invasion Migration- It refers to arrival of propagules, dispersion. Ecesis- It involves establishment and initial growth of vegetation. Aggregation- It involves increase in number of species. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only. 36 Competition- As vegetation became well established, grew, and spread, various species began to compete for space, light and nutrients. This phase is called competition. Stabilization- Reaction phase leads to development of a climax community. https://www.youtube.com/watch?v=8ceDE01iWLE 37  Study of some common ecosystems Terrestrial ecosystem o Grassland ecosystem o Desert ecosystem o Forest ecosystem Aquatic ecosystem o Pond ecosystem o Ocean ecosystem This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Forest Ecosystem Abiotic Components Inorganic and organic substances found in the soil, climatic factors, e.g., temperature, humidity, rainfall, and light. Biotic Components Producers Different kinds of trees depending upon the climate Consumers Different kinds of primary, secondary, and tertiary consumers, e.g., deer, elephant, snakes, lizards, lion, and tiger Decomposers These are various kinds of bacteria and fungi  Tropical rain forest Notable features: – Found in tropical region (near the equator). – High rainfall, humidity and temperature – Large leaves – Rich in biodiversity – Fauna of these rainforests includes the jaguar, tapir, okapi, boa constrictor, African grey parrot, keel-billed toucan, crowned eagle, three-toed sloth, spider monkey, large flying fox and more. Layers – Emergent layer – Canopy – Understory – Forest floor Example: Amazon Rainforest, Congo Rainforest, Southeast Asian Rainforest etc. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Tropical deciduous forest Notable features: – Tropical deciduous forests form a natural cover almost all over India. – They are of two types-moist and dry. Moist forests are found on the eastern slopes of Western Ghats, North eastern parts of the Peninsular Chhota Nagpur plateau and along the Shiwaliks. – They shed there leaves for a particular period of time. – They are economically very important because of timber like sal and teak. – The animals found here are tiger, wolves, rabbit etc. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Sub-tropical forest Notable features: – Subtropical forests are within or bordering the tropical zone. – temperatures may vary only slightly over a year – Subtropical rainforests occur in Central America, the West Indies, India, Madagascar, mainland Southeast Asia, and the Philippines. – Small deciduous trees and shrubs are found. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Temperate rain forest Notable features: – The world's largest temperate rain forests are found on the Pacific coast of North America. – Temperate rain forests are also found in coastal Chile, Norway, the United Kingdom, Japan, Australia and New Zealand. – The mild weather conditions – Adequate rainfall – Coniferous trees dominate the forest – tall evergreen trees are also found – Animals: black bears, lynx, wolves etc. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Temperate deciduous forest Notable features: – Located in the mid-latitude areas (between the polar regions and the tropics). – The temperature varies widely from season to season with cold winters and hot, wet summers. – During the fall, trees change color and then lose their leaves. – Most of the trees are broadleaf trees such as oak, maple, beech, hickory and chestnut. – Animals: toad, chipmunk, gray squirrel, Yellow- breasted chat etc. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Evergreen coniferous forest Notable features: – They are found just in south of arctic tundra – Winters are long, cold and dry – Sunlight is available for few hours only – Soil has less nutrient and acidic – Major trees are Pine, Fir, Cedar etc. – Animals: moose, deer, reindeer, squirrels, wolves, bears, foxes, owls, woodpeckers hawks etc. This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Grassland Ecosystem Abiotic Components Inorganic elements (C, H, O, N, P, S), climatic components, temperature, rainfall, light, etc. Biotic Components Producers Mainly grasses with a few scattered trees Consumers Deer, rabbit, giraffe, etc., are herbivores, while wolf, leopard, etc., are carnivores Decomposers Mainly bacteria and fungi  Tropical grassland Notable features: – Located near the equator, between the Tropic of Cancer and the Tropic of Capricorn. – Although these areas are overall very dry, they do have a season of heavy rain. – Dominated by grasses – May have some drought-resistant, fire-resistant trees – Animals: giraffes, zebras, buffaloes, kangaroos, mice, moles, gophers, ground squirrels, snakes, worms, termites, beetles, lions, leopards, hyenas, and elephants. Examples: – Savannas This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Temperate grassland Notable features: – Trees and shrubs are completely absent or rare. – cold winters (-40 C) and hot summers (38 C) – Gentle slope – Animals: Rodents, bisons, wolves, hawks, owls etc. Examples: – Prairies (South America) – Pampas (Africa) – Velds (Central Europe) – Steppes (Asia) This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Polar grassland Notable features: – Severe cold and strong wind – Arctic wolf, arctic fox, reindeer, migratory birds and insects are found. Examples: – Arctic Tundra – Permafrost: Permafrost is soil, rock or sediment that is frozen for more than two consecutive years. In areas not overlain by ice, it exists beneath a layer of soil, rock or sediment.  Desert Ecosystem Characteristics: Deserts are arid ecosystems that receive fewer than 25 centimeters (10 inches) of precipitation a year. Abiotic Components Low rainfall, high temperature, and sandy soil Biotic Components Producers Predominantly shrubs, cactus, etc. Consumers Different insects, lizards, reptiles, rodents, birds, etc. Decomposers Various bacteria and fungi This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only. 50  Desert ecosystem About 1/5th of the earth surface is covered with desert Tropical desert – Notable features: It is the driest and hottest place on earth. Rainfall is sporadic and in some years no measurable precipitation falls at all. – Examples: Sahara, Kalahari, Thar, Mexican deserts, Great Australian desert. Temperate desert – Notable features: Temperate deserts can be much colder than tropical deserts The floor of the temperate desert is often covered by rocks and small pebbles – Examples: Mojave, Sonoran Deserts Cold desert – Notable features: cold deserts occur in temperate regions at higher latitudes hot summers but extremely cold winters. – Examples: Atacama, – Gobi, Great Basin, Namib, Iranian, Takla Makan, and Turkestan Distribution of hot and cold deserts on the map.  Pond Ecosystem Abiotic Components It includes organic and inorganic substances, atmospheric gases dissolved in water, minerals found in dissolved state, etc. Biotic Components Producers Submerged floating and emergent aquatic plants For example, hydrilla, etc. Consumers May be primary, secondary, or tertiary, e.g., small fishes, mollusca, etc. Decomposers Chiefly bacteria,fungi, etc. 53  Lake ecosystem Organisms of aquatic ecosystem – Planktons (Algae, rotifers: limited locomotion) – Nektons (Fishes: active swimmer) – Neustons (Floating plants) – Benthos (Bottom dweller: Snail) – Periphytons (Crustaceane) Zonation (Stratification) – Epilimnion (Warm, lighter, circulating surface layer) – Hypolimnion (Cold, viscous, non- circulating bottom layer)  Types of lakes Oligotrophic lakes (Low nutrient content) Eutrophic lake (High nutrient content) Dystrophic lake (Low pH Examples:Lake Suchar II in Poland, lakes Allgjuttern, Fiolen, and Brunnsjön in Sweden.) Endemic lakes (Ancient, deep, having endemic fauna) Desert salt lakes (High salt content Ex: Great Salt Lake northern Utah, United States) Volcanic lakes Mermictic lakes (Permanently stratified) Artificial lakes This material is for reference only. Points present in the slides are only for assistance and their elaboration are present in book. Examination questions will be in depth and can be solved by following text book only.  Ocean Ecosystem Abiotic Components Largest ecosystem on the Earth. Characterized by high salinity of water, the major ocean in the world are Pacific, Indian, Atlantic ocean and all. Biotic Components Producers Phytoplanktons For example, diatoms, microscopic algae and other organism are sea weed, red algae and brown algae etc. Consumers May be primary, secondary, or tertiary, e.g., small fishes, molluscs. Decomposers Chiefly bacteria, fungi, etc. 56  Oceans Notable features: – Marine ecosystems support a great diversity of life and variety of habitats. – The ocean is a major influence on weather and climate. – Plants: seaweeds, or marine algae (brown, green, red), sea grasses, phytoplankton – Animals: protozoans, marine invertebrates (echinoderms, mollusks, segmented and non-segmented worms, jellies, coral, sea anemones, hyroids) marine vertebrates (fishes, birds, mammals), and zooplankton. Zones – Coastal zone – Open sea Euphotic zone (Abundant sunlight, high photosynthetic activity) Bathyal zone (Dim light) Abyssal zone (Dark zone)  Streams Notable features: – Stages Mountain highland (Young River) Second phase (Middle Aged River) Third phase (Old River)  Oceans Notable features: – Marine ecosystems support a great diversity of life and variety of habitats. – The ocean is a major influence on weather and climate. – Plants: seaweeds, or marine algae (brown, green, red), sea grasses, phytoplankton – Animals: protozoans, marine invertebrates (echinoderms, mollusks, segmented and non-segmented worms, jellies, coral, sea anemones, hyroids) marine vertebrates (fishes, birds, mammals), and zooplankton. Zones – Coastal zone – Open sea Euphotic zone (Abundant sunlight, high photosynthetic activity) Bathyal zone (Dim light) Abyssal zone (Dark zone) Acknowledgment Some images, animation, and material have been taken from the following sources: Textbooks: PERSPECTIVE IN ENVIRONMENTAL STUDIES by ANUBHA KAUSHIK, C P KAUSHIK, NEW AGE INTERNATIONAL PUBLISHERS References Book: TEXTBOOK OF ENVIRONMENTAL STUDIES by D. DAVE AND S. S. KATEWA, CENGAGE LEARNING 3 All slides can be used for reading purpose only 60 Thanks